Shedding Light On Bacterial Infections

Scientists have replaced blood agar plates with flurophores for detecting hemolytic bacteria.

AsianScientist (Sep. 29, 2017) – In a study published in the journal ACS Sensors, researchers from the Temasek Life Sciences Laboratory and the National University of Singapore have developed a method to quickly and accurately detect harmful bacteria.

Beta-hemolytic bacteria are responsible for causing common illnesses such as sore throats and gut discomfort. The term beta-hemolytic is derived from the bacteria’s ability to produce an enzyme that breaks down red blood cells. Examples of such bacteria include Streptococcus and Listeria. The ability to accurately identify these pathogens can improve treatment for common diseases.

In this study, the researchers modified a diagnostic test that was first developed in the year 1903. More than a century ago, a patient’s sample would typically be smeared onto blood agar plates, and if beta-hemolytic bacteria were present, clear zones would form on the blood agar, which allow doctors to identify the type of bacterial infection.

Instead of blood, the researchers placed fluorophores, or light-emitting molecules, inside lipid vesicles. These liposomes served as the substrate on which bacteria were grown. While in the liposomes, the fluorescent molecules are packed together and remain dark.

When in the presence of beta-hemolytic bacteria, however, the liposomes are broken open, releasing the fluorophores which then give off a fluorescent signal. The test distinguished beta-hemolytic bacteria from control bacteria with 100 percent accuracy in six hours on agar plates, and with 99 percent accuracy in liquid broth within an hour.

The researchers noted that the method is rapid and cost-effective, making it ideal for diagnostics in developing countries.

The article can be found at: Sum et al. (2017) Beta-Hemolytic Bacteria Selectively Trigger Liposome Lysis, Enabling Rapid and Accurate Pathogen Detection.


Source: American Chemical Society; Photo: Shutterstock.
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